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Biomedical subjects

M Susser

Publications and source records attributed to M Susser.

At least 109 records · Page 6Linked to original sources

Voluntary health agencies as target populations for epidemiologic research.

The ability of two voluntary health agencies to provide suitable target populations for epidemiologic research was explored in a pilot study of epilepsy. The results suggest that, properly approached, voluntary agencies offer advantage for this purpose. In the first agency (Group A), subjects were recruited by mail, producing a response rate of 15%. In the second agency (Group B), subjects were recruited by telephone, producing a response rate of 87%. A structured, precoded telephone interview about personal and family history of seizure disorders was administered to both groups of subjects. Subjects in Group A gave permission to contact a higher proportion of their eligible relatives than did those in Group B (73 vs 57%). Permission was obtained more often for relatives reported to have had seizures (Group A 86%, Group B 78%) than for other relatives. 89% of relatives contacted directly agreed to be interviewed. Consent forms for medical record review were signed and returned by 95% of Group A and 77% of Group B subjects. Diagnoses of etiology and seizure type of epilepsy based on the interview data agreed with diagnosis based on the medical records in most cases. In first-degree relatives of subjects with epilepsy, reported rates of epilepsy did not appear to be seriously biased.

Adult↗

The choice of place of delivery. Effect of hospital level on mortality in all singleton births in New York City.

In an analysis of all singleton births and neonatal deaths with known birth weights and gestational ages in New York City maternity services during a three-year period (1976 to 1978), intensive care services at the hospital of birth were found to influence mortality only in preterm (less than 37 weeks' gestation) or low-birth-weight infants (less than 2251 g). By contrast, for infants who were born at term and of normal birth weight, mortality rates did not differ by level of perinatal care available at the hospital of birth. On the average, preterm and low-birth-weight infants were at a 24% higher risk of death if birth occurred outside of a level 3 center, regardless of whether birth occurred at a level 1 or level 2 hospital. Preterm and low-birth-weight infants, though constituting only 12% of births, accounted for 70% of neonatal deaths in New York City. The remaining infants, ie, those born at term and of normal birth weight, who experienced no measurable mortality advantage when born in a level 3 hospital, accounted for 88% of all births.

Birth Weight↗

Indicators and designs in genetic epidemiology: separating heredity and environment.

The problems of separating highly confounded hereditary and environmental factors are reviewed from an epidemiological point of view. Once the fact rather than the appearance of familial aggregation is established, one can search for and analyze strong indicators of either genetic or environmental effects, and ultimately attempt their separation by strong design. Indicators of genetic effects are classified according to the presence or absence of family recurrence. In the presence of family recurrence, three analytic approaches are available: segregation analysis, linkage, and heritability estimates. In the absence of family recurrence, biological markers and endogamous groups can be used. Indicators of environmental effects are also classified according to the presence or absence of family recurrence of a disorder. In the presence of family recurrence, three environmental indicators are considered: non-Mendelian clustering, such as time of onset versus age in family clusters, and sex clusters; cohabitational effects; and maternal transmission. In the absence of family recurrence, environmental indicators include secular trends, migration, time and place clusters, family size, and birth order. Designs that aim to separate heredity and environment include twin studies, fixed clusters that include a variety of degrees of relatedness (particularly the family set-design), and comparisons of separately reared relatives. The strengths and weaknesses of twin studies and family set designs are reviewed. Separately reared relatives provide the most cogent tests of genetic and environmental hypotheses. Among these, separated twin pairs, half-sibs, and relatives separated through institutional placement or adoption are considered. Adoption strategies are illustrated by the Danish adoption studies of schizophrenia, criminality, and alcoholism, and these studies are reanalyzed from the perspective of epidemiological case-control and cohort studies. Finally, the potential uses of multiple family settings as they occur in the general population are briefly discussed.

Environment↗

Vaginal spermicides and spontaneous abortion of known karyotype.

The relationship between spermicide use and spontaneous abortion was examined in a New York City case-control study carried out during 1974-1982. In a series of matched sample analyses, case groups categorized by karyotype of the abortus were compared to a control group of prenatal patients with respect to spermicide use. Spermicide use was defined in terms of proximity to the date of conception of the study pregnancy and duration of the episode of use most recent to the study pregnancy. There was no association between spermicide use defined either in terms of recency or duration of use and chromosomally normal abortions, which comprise about 60% of all spontaneous abortions. Similarly, there was no association between spermicide use and the various types of chromosomally abnormal abortions, with the exception of trisomic abortion. Spermicide use for more than one year at any time prior to conception was more common in the cases aborting trisomic conceptions than in the control group (odds ratio = 1.9, confidence limits = 1.2, 3.0). There was evidence to suggest that the association varied with maternal age and phase of entrance into the study.

Abortion, Spontaneous↗

An assessment of the effects of maternal age and parity in different components of perinatal mortality.

Perinatal mortality has several components which may have distinct epidemiologic features. In an investigation of the total singleton birth population of New York City in 1976-1978 (n = 320,726), the authors divided perinatal mortality into four components: late fetal deaths that occurred before labor (late antepartum fetal deaths), fetal deaths during labor (intrapartum fetal deaths), neonatal deaths, and perinatal deaths attributed to congenital anomalies, and they assessed the relation of each of these to maternal age and parity, controlling for relevant confounding factors. In analyses which controlled for prior fetal loss, type of service (public vs. private), race, marital status, and mother's educational attainment in a multiple logistic regression model, the authors found that: 1) increasing maternal age was strongly associated with antepartum fetal deaths but not with intrapartum fetal deaths, while older maternal age was also associated with perinatal deaths attributed to congenital anomalies; 2) high parity bore a strong relationship to intrapartum fetal deaths, but none to antepartum fetal deaths, neonatal deaths, or congenital anomaly deaths; and 3) for neonatal death, there was a statistically significant (p less than 0.001) interaction between parity and age such that mothers over 34 years old having their first birth were at especially high risk.

Adult↗

Induced abortion and the chromosomal characteristics of subsequent miscarriages (spontaneous abortions).

Data from a case-control study of miscarriages (spontaneous abortions) were used to test whether single and multiple induced abortions are associated with miscarriage in subsequent euploid (chromosomally normal) pregnancies. Cases and controls were identified in three New York City hospitals between April 1974 and November 1982. It was hypothesized that, if induced abortion increased the risk of subsequent miscarriage, an association would be observed with euploid but not aneuploid (chromosomally abnormal) miscarriage. The frequencies of single and multiple induced abortions among euploid cases and aneuploid cases were compared with those among controls. Among both private and public patients, the proportion of women reporting a single induced abortion was similar in euploid cases and in aneuploid cases compared to controls. Among public patients only, the proportions reporting multiple induced abortions were also similar in euploid cases and in aneuploid cases compared to controls (odds ratios = 0.9 and 1.0, respectively). In contrast, among private patients, the proportion reporting multiple induced abortions was raised among euploid cases (odds ratio = 2.2, 95% confidence interval = 1.3-3.7), although not among aneuploid cases. This association was strongest when the first induced abortion was carried out before 1973, at a young age, or with a procedure other than suction curettage. In public patients, the associations with miscarriage did not vary with characteristics of the first induced abortion, but multiple induced abortion histories when the first two induced abortions occurred before 1973 were in excess among euploid cases compared to controls. These results suggest that, for both private and public patients, neither single nor multiple induced abortions as now performed are likely to increase the risk of miscarriage in subsequent pregnancies. They also suggest a mechanical origin for some miscarriages.

Abortion, Induced↗

Characteristics of women with recurrent spontaneous abortions and women with favorable reproductive histories.

Women with a history of recurrent spontaneous abortions (repeaters) are compared with women who have had live births and no spontaneous abortions (multiparae) and women who have had live births and only one spontaneous abortion (sporadics) to identify characteristics of the women and their abortuses that might predict subsequent fetal loss. A number of risk factors for recurrent spontaneous abortion have been identified: the loss of a chromosomally normal conception, loss after the first trimester of pregnancy, a delay in conceiving prior to the study pregnancy, a diagnosis of cervical incompetence, and a history of very low birthweight deliveries. The odds ratios associated with being a repeater vary from 1.4 to 5.6 depending on the number of characteristics present.

Abortion, Habitual↗

Seizures in public places in New York City.

The frequency of police aid to persons experiencing seizures in public in New York City in 1977 was examined as an index of uncontrolled seizure disorders, and as a pointer to variations in seizure frequencies by age, sex, and ethnicity. The overall rate of assistance to persons with public seizures was 5.4 per 10,000 person years. For Blacks the rate was more than double that for Whites and "Hispanics" (10, 4.7, and 4 per 10,000 person years, respectively). Males were assisted about 2.5 times more often than females (8.2 vs 3.3 per 10,000 person years). Among Black males, young adults and those of late middle age had the most pronounced excess over White males of the same ages (26.1 and 23.1 vs 7.8 and 4.0, respectively, per 10,000 person years). These variations underscore an unmet need for medical care for seizures that is especially marked in particular ethnic, sex, and age groups.

Adolescent↗

Medical care and preterm infants of normal birth weight.

Preterm infants of normal birth weight (born before 37 completed weeks of gestation and weighing more than 2,250 g) experience a neonatal mortality risk almost four times higher than do term infants in the same weight range. In an analysis of the effect of hospital level of birth on neonatal mortality, such preterm normal weight infants were found to experience higher mortality if born outside of a Level 3 (tertiary care) center. For all singleton infants in this weight-gestation category born in New York City maternity services during a 3-year period (N = 23,257), the relative mortality risk for Level 1 births (compared with Level 3) was 1.72 (P less than .01) and for Level 2 births 1.47 (P less than .05). The excess mortality at Level 1 and Level 2 units was almost entirely due to a more than twofold higher death rate in black infants born in these units. Several potentially confounding socioeconomic, demographic, and biologic variables entered into a logistic regression model could not account for the higher mortality rates for black infants born in Level 1 and Level 2 units. Among black infants born at Level 1 units, deaths in preterm normal birth weight infants were less likely to occur in a receiving tertiary care center than were either deaths in low birth weight infants or deaths in term normal weight infants, suggesting that the need for special care of preterm normal birth weight infants is underestimated in some hospitals without newborn intensive care units.

Analysis of Variance↗

Fetal death during labor: an epidemiologic indicator of level of obstetric care.

The effect of level of perinatal care on rates of intrapartum fetal death was studied in births of infants weighing greater than 1000 gm in New York City in 1976 to 1978. With potential confounding by birth weight, gestational age, and several other variables controlled, intrapartum fetal death rates decreased as intensiveness of care increased. Compared with births in Level 3 maternity units (perinatal intensive care), births in Level 1 units (community hospitals) had a 61% excess risk of intrapartum fetal death (p less than 0.01) and births in Level 2 units (intermediate level of care) had a 35% excess risk (p = 0.06). The effect of hospital level on intrapartum fetal death rates could not be attributed to differences in the classification of fetal deaths during labor across hospital levels, since no compensatory differences in late antepartum fetal death rates were found. Our findings in a total population are compatible with several studies carried out in single hospitals that have reported declines in intrapartum fetal death rates, especially in births more closely attended during labor. Fetal deaths that occur in labor, as contrasted with fetal deaths occurring before labor, constitute a perinatal outcome that is especially sensitive to level of obstetric care.

Birth Weight↗

Fever during pregnancy and spontaneous abortion.

The hypothesis that maternal fever during pregnancy is a risk factor for spontaneous abortion was tested in a case-control study by comparing the frequencies and timing of fevers of 100 F (37.78 C) or more among three groups of women: women having euploid abortions, women having aneuploid abortions, and women delivering at 28 weeks gestation or later (controls). Cases and controls were identified in three New York City hospitals between August 1979 and June 1982. It was hypothesized that if fever was an antecedent, rather than a symptom of spontaneous abortion, an association would be detected with euploid but not with aneuploid abortions. Among public patients, reported fevers were significantly more frequent among euploid abortions than among controls (18% vs. 7.1%, odds ratio = 2.96), whereas reported fevers were not more frequent among aneuploid abortions (3.9% vs. 7.1%, odds ratio = 0.52). It was also postulated that variation in the strength of the association of fever with euploid abortion with the duration of the interval between the fever and the abortion might yield insight about mechanisms underlying an association. The odds ratios for fever occurring at three intervals--in the same calendar month as a euploid abortion, one month before, and two or more months before--were 6.04, 3.28, and 1.41, respectively. The findings for private patients--for whom a control group was not recruited--are compatible with those for public patients although not statistically significant: the odds of fever with euploid abortion were 2.18 times those with aneuploid abortion.

Abortion, Spontaneous↗